


If You Can’t Breed ‘Em, Join ‘Em

by brooklynapple



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Barbs, Demonic Beast Marianne, Don't say I didn't warn you, F/F, Milking, Monsterfucking, Spines, acidic cum, demonic beasts in love, hilda's demonic strap, really cursed demonic beast sex, yet somehow there are also wholesome parts
Language: English
Status: Completed
Published: 2020-10-29
Updated: 2020-10-29
Packaged: 2021-03-09 00:41:20
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,423
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27255853
Author URL: https://archiveofourown.org/users/brooklynapple/pseuds/brooklynapple
Summary: Hilda makes a special toy to help satisfy her demonic beast girlfriend, and gets way more than she bargained for.
Relationships: Marianne von Edmund/Hilda Valentine Goneril
Comments: 2
Kudos: 27
Collections: FE3H Monsterfucking Weekend 2020





	If You Can’t Breed ‘Em, Join ‘Em

**Author's Note:**

> Happy FE3H Monsterfucking Weekend, the most magical, wonderful and horny time of the year! You couldn’t ask for a more perfect event for some filthy Marihilda smut featuring feral, demonic beast Marianne. I think I really outdid myself this time with the cursed monsterfucking. Hope you enjoy!

“I finally finished it, Mari! Just in the nick of time, too!”

Hilda burst through the door of the room she shared with Marianne at Garreg Mach as the sun sank low in the sky. She pulled a long, cloth-covered package out from under her arm and held it out to Marianne proudly.

Marianne’s eyes widened. “Is that what I think it is?” She greeted Hilda with a kiss on the cheek and eagerly unwrapped the package. 

“I made it just as big, spiny and scaly as you described,” Hilda said with a grin.

Marianne opened the box and removed what couldn’t be mistaken for anything other than a large, intricately-carved cock. It was at least a foot long and easily as thick as her wrist, and that was far from the most unusual thing about it. Its impressive length and girth was covered in a grey-green, scaly texture, and spines, bumps and ridges protruded from it at varying intervals. The whole thing curved wickedly upwards and ended in a thick, ridged cockhead. 

Even though she had made it herself, Hilda found it absolutely terrifying. 

“Oh, Hilda, it’s absolutely perfect! This is just what I’ve been craving during my crest times.” Marianne threw her arms around Hilda in a big hug. 

“I’m glad you like it, sweetie! But um, are you really sure that you want me to use it on you tonight? I know you said you needed something bigger than our normal strap, and I know you like it a lot rougher during your crest transformations, but this thing looks pretty scary. I don’t want to hurt you or do anything you don’t want!”

“I promise it won’t be like that, Hilda. When the beast takes over all I can think about is how much I need to, well, mate.” A bit of color crept into her cheeks. “And I know this might sound strange, but when I’m like that there’s a part of me that wants it to hurt. I think that might be how demonic beast mating works.” She was fully blushing now. “If that’s too much for you I understand. We don’t have to do this.”

“Mari sweetie, I’m here to give you what you need. I didn’t spend months making this gorgeously evil looking cock just to get cold feet at the thought of actually using it with you.” She stroked the toy with a grin. “If you’re sure you want this, then I’m in. I’ll be the best, horniest beast you’ve ever seen. And if you need it to hurt a little, well, I can make that happen too. I figure it’ll be like the time Claude asked me to choke him. Which I totally wasn’t supposed to tell you about.”

Marianne laughed, and Hilda pulled her in for a kiss. 

“Thank you, Hilda. You’re the best girlfriend I could ever have asked for. Shall I make us some tea while we wait for moonrise?”

************

By now Hilda was used to Marianne’s monthly transformations, though it had been a little startling when they first started dating to learn that her girlfriend turned into a human/demonic beast hybrid once every month on the full moon.

A lesser woman might have been scared off by all the scales and teeth and claws, not to mention the fact that demonic beast Marianne was insanely strong and even more insanely horny. But Hilda Valentine Goneril never backed down from a challenge, and besides, this was  _ Marianne.  _ No amount of scales and teeth and growling about mating was going to keep her from making her beast girl happy. 

So Hilda added extra crunches and quad exercises to her routine, shifted her sleep schedule right before full moon nights, and leaned into the inner monsterfucker that she had to admit had always been there if she was being honest with herself.

She figured that at this point she could handle just about anything that her horny demonic girlfriend threw her way. As Marianne entered the first throes of her transformation, Hilda strapped the ridiculously large demonic cock between her legs. She sidled over to her girlfriend on the bed and stroked the toy while wiggling her eyebrows suggestively.

“Okay baby, do your magic thing and I’ll be ready to give you the demon dicking you deserve!” She winked and flashed a grin.

Marianne looked down at Hilda’s enormous demon cock and  _ growled.  _ She extended a claw-tipped hand and wrapped it around the toy. Her eyes flashed a deep blood red as magic flowed into the wickedly curved appendage. 

Hilda felt something stirring deep inside herself. Suddenly, her whole world shifted.

She had suspected that the demonic strap would feel different than a regular strap once the magic was active. What she hadn’t counted on were the demonic urges and sensations that seized her brain with overwhelming force. 

She looked down at her mate writhing on the bed and could  _ smell _ the scent of her heat pouring off of her. The demonic cock twitched to life between her legs, swelling to immense proportions that no human cock could match. The scales bristled, and the spines flared out and elongated along its length. A drop of pale green liquid coalesced at the tip and dripped onto Marianne’s scale-covered stomach. It smoked and gave off an acidic smell as it partially ate through the scaly armor.

Hilda snarled. Her mate was wet and needy and in heat underneath her, and her cock was hard and dripping. The urge to breed was all consuming. She needed to mount Marianne  _ now.  _

Marianne growled and whimpered as she saw that Hilda’s cock was ready for her. She came to all fours and pressed back against Hilda, rubbing the cock against her slick, scaly folds. She hissed as the acidic precum made contact with her sensitive skin and lashed her tail in pleasure.

Hilda groaned and shifted her hips to let her stinging juices coat Marianne’s labia and clit. Her cock throbbed and swelled as Marianne’s wetness coated it. When she could stand it no longer, she grabbed Marianne’s hips and mounted her, splitting her open with her thick, ridged cockhead and thrusting roughly inside her. 

Marianne yowled and thrashed as Hilda settled on top of her and sank her pointed teeth into Marianne’s shoulder. The acid from Hilda’s cock burned inside her, and Hilda felt the barbs and spines scrape against her mate’s wet, scaly walls. She could tell from the way Marianne whimpered and writhed that the pain was nearly as overwhelming as the pleasure, and the knowledge only made her cock grow harder. 

Hilda pounded into Marianne with rapid, steady strokes, growling and gnawing at her shoulder. Her demonic cock swelled inside Marianne, and the urge to fill and dominate her grew stronger. Marianne twisted and whined underneath her, and Hilda growled and bit down hard to warn her mate to stay still and submit to being bred. She could feel her barbed cock getting harder and thicker, and knew that more acidic fluid was leaking out to coat Marianne’s insides and prepare her to be pumped full of Hilda’s juices. 

Marianne let out a high-pitched whine and Hilda felt her scaly walls clench around her cock. Suddenly, the barbs extended fully, locking her cock in place inside her mate. She could move just enough to get a small amount of friction, but it wasn’t enough and she growled in frustration. Then Marianne began to pulse around her. 

Hilda had felt Marianne contract around the human-shaped magic cock when they’d used it during non-beast sex, but this was something altogether different. Marianne was rhythmically and forcefully milking her cock in peristaltic waves. Hilda growled again as she felt her cock twitch and spasm and swell to aching hardness, and then all at once she was coming hard inside her mate. Each contraction from Marianne drew forth a fresh spurt of Hilda’s acidic seed, and it just kept going until Hilda had filled Marianne with more demonic juices than she had thought possible. 

Marianne was panting and mewling and writhing in agonized pleasure as she continued to coax more demonic cum from Hilda’s twitching cock. After several long minutes and dozens of contractions, she went limp underneath Hilda with a quiet, contented growl. 

Hilda felt an overwhelming sense of satisfaction at having thoroughly dominated and bred her mate. Marianne was hers, and no one else could take her. Her cock was still firmly lodged inside Marianne, held fast by the barbs and spines. It was still hard, though she no longer felt that urgent ache. She settled on top of Marianne and waited, content to stay mounted on her mate and inhale the scent of Marianne’s heat. She licked at the bite marks on Marianne’s shoulder.

Before long Marianne started to whine and shift underneath her, pressing her hips back into Hilda as though asking to be fucked again. Hilda felt her cock start to swell anew. A quiet, distant voice from the tiny part of her that was still human wondered how many times they were going to do this, but it was quickly silenced by a growing need to breed her mate once more.

Marianne had started to paw between her legs with one of her hands, and Hilda batted it away to reach down herself and feel her mate’s wetness. She let out a low, hungry growl as she discovered that Marianne’s clit had swollen and elongated with need. She pumped and stroked it while moving inside Marianne with the shallow, unsatisfying thrusts that the barbs allowed.

Marianne whimpered and whined and pushed into Hilda’s hand. Soon Hilda’s efforts made Marianne’s hips buck and her contractions began again with the same rhythmic pulsing designed to draw every last bit of seed from Hilda’s throbbing cock. Hilda growled in satisfaction and emptied herself into her mate again and again. 

They stayed fused that way for several hours, with bouts of mating punctuated by bouts of rest. By the end of the night Hilda had lost count of how many times she filled Marianne’s pulsing cunt with her hot, acidic seed. 

At long last, after an especially prolonged series of contractions that left acidic cum leaking out from around Hilda’s cock and dripping down to leave scorched holes in the bedsheets, Hilda felt the spines in her cock retract. She pulled out of Marianne and collapsed on the bed next to her, panting and spent and completely exhausted. 

Marianne rolled over on one side and went limp. Hilda watched as her scales faded and her claws retracted. She felt the magic dissipating from the cock between her legs, which was rapidly reverting to an inert, intricately-carved toy. The acidic juices coating Marianne, Hilda and the bedsheets evaporated into a thin mist that quickly dissipated in the air.

Hilda felt her world shift back into sanity as the magic faded. She reached out to put a gentle hand on Marianne’s shoulder. “Holy shit, Marianne, that was intense. Are you okay? I had no idea the magic was going to affect me like that. I was all set to pretend to be a beast for you, but that spell made me feel like I really was one. Did I hurt you? I mean like, in a way you didn’t want?”

Marianne gave her a tired smile and kissed the hand caressing her shoulder. “Hilda, you did great. That was just what I needed. I’m sorry if I didn’t do a good job describing what the spell would do to you, but you handled it so well. And now maybe you have a sense of what it feels like during my crest time.”

“I thought I had a pretty good sense of what your crest time must be like, but wow, I had no idea. I’ve never felt so horny in my life. All I could think about was how much I needed to mate with you right that second.” She grinned. “It was amazing.”

Marianne scooted closer to snuggle into her. “So it wasn’t too much for you, then? I know the idea of breeding like demonic beasts would be horrifying for a lot of people. Not everyone wants to be with a monster.”

Hilda wrapped her arms around Marianne and kissed her forehead. “Mari, I knew what I was signing up for when I asked you to be mine. You’re not just  _ a _ monster, you’re  _ my _ monster. And I’m happy to give you whatever you need, including super horny beast mating. Which I have to admit was pretty hot. But are you sure you’re okay, with all of the spikes and acid and biting and stuff? I know you said you wanted to be hurt, but that was a lot.”

“Yes, I’m sure. I’m definitely going to be sore tomorrow, but most of the damage caused by the acid and spikes healed up when I transformed back. I know it must have been a lot to process while it was happening, but I promise it felt good. Those are the things my body craves during my heats.”

“I’m always happy to satisfy my horny little monster. Are there any other side effects I should be aware of from all of that, um, breeding?”

Marianne looked confused for a moment, and then laughed. “Oh, are you asking if I could get pregnant? No, as far as I can tell from the research I’ve done, nothing from my crest transformation or the magic I used on your toy is permanent. You saw how the acid vanished when the spell faded. Even if it was somehow compatible enough with human physiology to impregnate someone, all trace of it disappears when the spell is gone. I don’t think we have anything to worry about.”

“Aww, so you’re saying we won’t be getting any little demonic bundles of joy? I was starting to get excited thinking about the cute accessories I could make for their tiny horns!”

Marianne giggled, and Hilda pulled her closer. “Hilda, thank you for everything tonight. Not many people would have done what you just did for me. I love you so much.”

“I love you too, sweetie. And I have to admit that being a super horny demonic beast was pretty fun. Now that I know what to expect, I kind of can’t wait until your next crest time. I’ll give you the best breeding you’ve had in your life!”

She winked, and Marianne mustered just enough energy to roll her eyes before falling fast asleep. 

**Author's Note:**

> I’ll be posting one more piece for #FE3HMonsterfuckingWeekend - a marihildahapistance foursome that will go up on October 31 for the confluence of polyship week and monsterfucking weekend. Stay tuned!
> 
> For more horny (and wholesome) hijinks, you can follow me on [Twitter](https://twitter.com/quorniya).


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